Can you show us Europeans putting guns to these African leaders heads and forcing them to sell the slaves? The only examples we see of this is really in modern day Angola with the Portuguese. The bolded I am not sure what you are getting at because the Atlantic slave trade was partially a trade. The colonization of Africa was a
conquest after Europeans reached industrialization. So they wouldn't be able to say "no."
Like I said all we can do is learn and not allow this to happen again. While praising the West Africans who DID resist like
@Samori Toure mentioned. Denying the role SOME West Africans played in selling human capital is just living in fantasy world. Of course we should not cast blame on MODERN West Africans who had nothing to do with it. So again not sure what to argue? These leaders weren't STUPID they were able to create powerful kingdoms i.e Oyo, Ashanti, Dahomey, etc.